Conventional dermatomes are used for cutting skin tissue to obtain a transplantable skin graft. A skin graft is a patch of healthy skin that is taken from one area of the body or donor site to cover a different damaged or skinless area of the body. Typically, known dermatomes have a head with a flat blade secured to the bottom of the head by a bottom plate. The blade is fixed between the head and the bottom plate with the sharp edge of the blade facing forward. The blade is fixed in a forward and rearward direction while being free to oscillate transversely to create a side-to-side slicing motion for cutting the tissue. The blade is connected to a motor in the device to reciprocate the blade. In use, the dermatome is held so that the blade lies slightly angled relative to the tissue surface to be cut and the blade edge is advanced against the tissue in a direction perpendicular to the direction of oscillation of the blade.
In order to provide a smooth continuous cut that forms straight side edges for the skin graft, the blade must be properly assembled to a dermatome head of an appropriate size. In other words, the width of the blade must match the width of the dermatome head to be used. If the blade is too wide for the dermatome, the lateral ends of the blade will be unsupported and will cause uncontrolled cuts or may cause bending of the blade that increases the dulling of the blade.
Also, blades are sometimes mounted on a carrier which is easier and safer to grasp than the blade and which interconnects the blade to the head of the dermatome and the motor. When the carrier is the same width as the blade, which is often the case, and if the carrier is too large for the dermatome and extends laterally outward beyond the bottom plate with the blade, the contact between the carrier and the skin tissue may cause damage to the tissue.
If the blade is too small, tissue may be pinched between the lateral ends of the bottom plate and the lateral ends of the blade which can lead to rough or jagged edges and a non-continuous cut.
Moreover, if the blade is assembled upside-down on the dermatome, a sharp blade edge having a certain slope relative to the surface of the tissue will be oriented incorrectly and may cause increased dulling of the blade or uneven cuts. Furthermore, some known dermatomes are adjustable to control the thickness of the skin graft. In this case, the known dermatomes have a control bar for being placed on top of a skin tissue surface. The control bar has an adjustable height and has a predetermined range of distances to the blade when the blade is properly assembled on the dermatome. Thus, setting the height of the control bar, sets the depth for the blade under the tissue surface. If the blade is upside-down on the dermatome (where the blade edge still faces forward on the dermatome), the blade may not be set at the expected distance from the control bar. This can occur because either the blade is not properly sitting flush on the dermatome head or the blade is mounted on one side of its carrier (top or bottom) such that mounting the blade and the carrier upside-down places the blade an undesired distance from the control bar. This undesired and unexpected vertical position of the blade can result in undesired skin graft thicknesses.
The known adjustable dermatomes also typically have a lever for shifting the position of the control bar to set the thickness of the skin graft. If the lever is set incorrectly or the switch and/or the control bar are accidentally shifted or bumped, it can result in an incorrect graft thickness. Thus, it would be desirable to have a dermatome that reduces the risk of errors relating to placement of the blade assembly on a dermatome head, and calibration of the dermatome to obtain a desired thickness of the skin graft.